It shouldn’t be explained. The girls should light, שאף הן היו באותו הנס. I encourage my (above Bas Mitzvah age) daughter to light (but I don’t force her to). [My younger daughters need no encouragement.]
My wife does not light, mostly because her mother doesn’t either. My father in law, who is a תלמיד חכם, explained this with the rule of אשתו כגופו. I don’t exactly understand the application of that concept here, but I went along with his פסק.